The invention relates to a method as well as a device for providing a substrate with an imprint (in particular with printing ink). It also relates to such a substrate, provided with an imprint, which can be obtained using the method.
The starting point of the invention is a method with the following properties: Firstly, for instance with the aid of one or more inkjet print heads (e.g. inkjet technology), liquid printing ink is printed on a (transfer) strip. The printing ink is made to dry at least partially on the strip. In the case of drying, liquid (water, solvent) escapes from the printing ink, which substantially consists of this carrier liquid and pigment particles in particular dispersed therein, in particular with diameters of between 20 and 100 nm. In the case of partial drying, residual liquid remains in the printing ink. The partial drying is brought about in particular by heating the strip. The printing ink which is liquid when it exits the inkjet print head (low viscosity) changes here into a more solid paste (high viscosity) on the strip. In a subsequent step the at least partially dried printing ink, thus the paste, is moved from the strip to the substrate or transferred to the substrate.
The method makes it possible to print particularly small structures, in particular dot structures, in the range of between 5 μm and 50 μm in diameter. In particular, the printing ink does not run on the substrate, because it is already dried on the strip beforehand to form a highly viscous material.
A method on which the present method draws is described in WO 96/31808 A1. There, instead of a (transfer) strip to which the liquid printing ink is applied and on which it is dried, a corresponding roller is provided.
An offset printing machine is known from EP1 719 622 A2, in which a phase change ink is applied to a transfer apparatus of the printing machine and transferred to a substrate by means of this.
WO 93/07000 describes an inkjet printing system in which, by means of a print head, ink is applied to a transfer roller and transferred to a substrate by means of this.
DE 10 2009 040 359 A1 describes a method in which an adhesive layer is applied to a substrate, which is then provided with a film transfer layer.